
public class MallardDuck implements Quackable {
	
	Observable observable;
	
	public MallardDuck()
	{
		observable = new Observable(this);
	}
	
	public void quack()
	{
		System.out.println("Quack");
		notifyObservers();
	}
	
	public void registerObserver(Observer observer)
	{
		observable.registerObserver(observer);
	}
	
	public void notifyObservers()
	{
		observable.notifyObservers();
	}
}
